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US 5,694,096 AGranted
Surface acoustic wave filter
AssigneeMurata Manufacturing Co., Ltd.
InventorsTadamasa Ushiroku, Hideharu Ieki
Life of this patent
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Abstract
A surface acoustic wave (SAW) filter includes a plurality of interdigital transducers located on a piezoelectric substrate along a surface wave propagation direction, at least a single one-port SAW resonator connected in series with an output side of the SAW filter, while the resonance frequency of the SAW resonator is set at a level which is higher than the passband of the SAW filter.
Claims22
A surface acoustic wave filter comprising:
- a piezoelectric substrate;
- a plurality of interdigital transducers formed on said piezoelectric substrate and arranged along a surface wave propagation direction, said plurality of interdigital transducers forming a surface acoustic wave filter part having input and output sides and a pass band;
- and
- a one-port SAW resonator which is not located along said surface wave propagation direction and which has at least one interdigital transducer, said one-port SAW resonator being connected in series with one of said input and output sides of said surface acoustic wave filter part, an antiresonance frequency of said one-port SAW resonator being set at a frequency level higher than said pass band of the surface acoustic wave filter part.
1 more element
A surface acoustic wave filter, comprising:
- a piezoelectric substrate;
- a surface acoustic wave filter part provided on said piezoelectric substrate and having input and output sides and a pass band, said surface acoustic wave filter part including a plurality of interdigital transducers and a pair of reflectors located on respective sides of said plurality of interdigital transducers and along a surface wave propagation direction of said plurality of interdigital transducers;
- a one-port SAW resonator which is not located along said surface wave propagation direction and which has at least one interdigital transducer, said one-port SAW resonator being connected in series with one of said input and output sides of said surface acoustic wave filter part, an antiresonance frequency of said one-port SAW resonator being set at a frequency level higher than said pass band of said surface acoustic wave filter part.
Dependencies are inferred from the claim text.